import { Client } from 'minio';
import { MinioConfig } from '../config';

/**
 * Service for handling MinIO operations
 */
export class MinioService {
  private client: Client;
  private bucketName: string;
  private readonly defaultExpiry = 60 * 60; // 1 hour in seconds
  private initialized = false;
  /**
   * Creates a new MinioService instance
   * @param config - MinIO configuration
   */
  constructor(config: MinioConfig) {
    this.client = new Client(config);
    this.bucketName = config.bucketName;
  }

  /**
   * Initializes the MinIO service by ensuring the bucket exists
   */
  public async initialize(): Promise<void> {
    if (this.initialized) {
      return;
    }
    const bucketExists = await this.client.bucketExists(this.bucketName);
    if (!bucketExists) {
      await this.client.makeBucket(this.bucketName, 'us-east-1');
      // Set the bucket policy to allow public read access
      const policy = {
        Version: '2012-10-17',
        Statement: [
          {
            Effect: 'Allow',
            Principal: { AWS: ['*'] },
            Action: ['s3:GetObject'],
            Resource: [`arn:aws:s3:::${this.bucketName}/*`],
          },
        ],
      };
      await this.client.setBucketPolicy(
        this.bucketName,
        JSON.stringify(policy)
      );
    }
    this.initialized = true;
  }

  /**
   * Generates a presigned URL for uploading a file
   * @param objectName - Name of the object to upload
   * @param expiryInSeconds - Expiry time in seconds (default: 1 hour)
   * @returns Presigned URL for uploading
   */
  public async generateUploadUrl(
    objectName: string,
    expiryInSeconds: number = this.defaultExpiry
  ): Promise<string> {
    return this.client.presignedPutObject(
      this.bucketName,
      objectName,
      expiryInSeconds
    );
  }

  /**
   * Generates a presigned URL for downloading a file
   * @param objectName - Name of the object to download
   * @param expiryInSeconds - Expiry time in seconds (default: 1 hour)
   * @returns Presigned URL for downloading
   */
  public async generateDownloadUrl(
    objectName: string,
    expiryInSeconds: number = this.defaultExpiry
  ): Promise<string> {
    return this.client.presignedGetObject(
      this.bucketName,
      objectName,
      expiryInSeconds
    );
  }

  /**
   * Checks if an object exists in the bucket
   * @param objectName - Name of the object to check
   * @returns True if the object exists, false otherwise
   */
  public async objectExists(objectName: string): Promise<boolean> {
    try {
      await this.client.statObject(this.bucketName, objectName);
      return true;
    } catch (_error) {
      return false;
    }
  }

  /**
   * Deletes an object from the bucket
   * @param objectName - Name of the object to delete
   */
  public async deleteObject(objectName: string): Promise<void> {
    await this.client.removeObject(this.bucketName, objectName);
  }
}